How can we ask our poets both for careful technique and for wild surprise? How can we even talk about poetry in general—how it works, what makes it good, how to read it—if the best poems stand apart from all rules, all programs? Longenbach (The Iron Key) enjoyed an international reputation as a scholar of modern poetry for more than a decade before his own verse found success; in this collection of essays, more than in any of his previous books, the poet’s hand and the critical ear combine. Robert Lowell, Emily Dickinson, and John Ashbery get star turns in some chapters, but the presiding spirits, examined at length, are W.B. Yeats, Ezra Pound and William Shakespeare, who show how poems need restraint and excess, craft and mystery, how literary style can seem “more magical than logical” and yet make sense when examined, and how “the thought provoked by the poem’s occasion” can drive both lyric and dramatic verse into new forms of “discovery, as unpredictably linear as it is purposeful.” Never too academic, Longenbach introduces not just great writers, but ways to think about them, ways to see how their works confront death, pursue self-doubt, and overcome their own initial limits. (Mar.)